## Essential University Physics: Volume 1 (3rd Edition)

We know that the center of mass of the bowl is $-\frac{r}{5}$, and we know that since the mouse hits the edge of the bowl, the location of the overall center of mass is $r-\frac{r}{5}$. Since the bowl moves 1/10 of a diameter, we know that it moves 1/5 of a radius. Thus: $(r-\frac{r}{5})m_m=\frac{r}{5}m_b \\ 4m_m=m_b$